Pipette stopper

ABSTRACT

A screw-on bottle stopper has a pipette connected to a flexible chamber which can be squeezed through an opening in the stopper to suck up and expel the contents of the bottle. The chamber comprises two parts, a flexible part and a rigid one, tightness being ensured by the perfect nesting of the parts.

[111 3,820,576 [45] June 28, 1974 United States Patent [191 Torrent VIII Fig.J

Fig. 2

l PiPETTE sroPPER BACKGROUND OF THE INVENTION The invention relates to a screw-on bottle stopper incorporating a pipette.

For the use, storing and transportation of certain liquids which may have to be dispensed in small quantities, for example drop by drop, such as medicaments and perfumes for instance, bottles fitted with a pipette stopper are employed-All these bottles have the major defect that they are not sufficiently fluid-tight to withstand a notable difference between the inner pressure and the surrounding atmosphere without letting the contents escape. This occurs in particular when the bottle is in an aeroplane flying at high'altitude without being stored in a pressurized part of the plane.

THE STATE OF THE ART French patent application No. 2,000,973 and Italian patent No. 859,800 disclose a pipette stopper comprising a rigid hollow member forced into the stopper, a flexible and resilient chamber lodged within this member and .connected to a pipette, and a gasket located against the hollow member and destined to be clamped between the latter and the bottle. Due to specific problems set by both the manufacture of the device and the nature of the materials used, it is practically impossible to obtain the required resilient chamber in a unique piece, the chamber consisting of twovmoieties sealed together. Experience has shown that it is practically impossible to realize a perfectly tight seam, particularly when a special tightness is required in the case of the use of very fluid and volatile materials and when the devicehas to withstand a notable difference between the inner pressure and the surrounding atmosphere.

French patent No. 1,267,062 and British patent No. 946,1 l0 disclose a graduated screw-on dispenser comprising a flexible chamber, said chamber being constituted by two parts which are simply nested together. The junction of the two parts is realized solely by their nesting and it is therefore insufficiently tight, Moreover, the chamber is not shielded from the external environment by anyy rigid means.

"SUMMARY oF THE INVENTION The object of the present invention is to provide a pipette stopper which does not offer the disadvantages of the known devices. Said pipette stopper comprises a flexible chamber constituted by two parts, said parts being shielded from the external environment. When thepipette stopper is screwed onto a bottle, an absolute fluid-tightness is ensured by the perfect nesting of the two parts. It has been observed that the required fluidtightness was ensured even in the case of very fluid and volatile liquids and in cases where big differences existed between the inner pressure of the bottle and the surrounding atmosphere. Moreover, the pipette stopper of the present invention'is characterized by having a compact outer shape without projecting parts, and a construction which is simple and economic.

The pipette stopper according to the invention comprises an external cap intended to be fitted on a receptacle, such as a bottle, and a chamber lodged within the cap, said chamber being tightly clamped between this latter and the receptacle when the cap is fitted on the receptacle. The chamber is constituted by two parts nested one into the otherand tightly clamped together when the cap is fitted in position, one of the parts being connected to a tube communicating with the inner part of the chamber and immersed in the receptacle when the cap isfitted in position, and the other part comprising a flexible wall which may be compressed through an opening in the cap in order that by compression the air ofthe chamber is expelled and by subsequent release of pressure the liquid contents of the receptacle are sucked up through the tube into the pipette, and, when required, expelled from the latter by a new compression.

BRIEF DESCRIPTION OF THE DRAWING The invention will be described in detail with reference to the figures of the drawing, wherein:

FIG. 1 is a view in cross section of a first embodiment of the invention and FIGS. 2 and 3 are respective views in cross section of second and third variations of the above illustrated embodiment.

,DESCRIPTION OF THE PREFERRED EMBODIMENTS The pipette stopper which in FIG. l is shown screwed down on a bottle l comprises an external cap 2, made of rigid plastic material for instance having an inner thread 3 by means of which it can be screwed onto the bottlel l, as shown.

A chamber 4 is constituted by a piece 5, shaped in the form of a dish, connected to a tube 6 communicating with the inner part of chamber 4, said tube being immersed in the liquid contained in the bottle when the cap is fitted in position, and a second piece 7, equally shaped in the form of a dish, which nests itself by means of its skirt into the groove existing between the external wall of piece 5 and an annular protruding edge 8 of the latter.

The external wall of 5 comprises a thread 9 which en ables chamber 4, formed by 5 and 7, to be screwed into cap 2, the chamber butting against a protruding edge lshaped in the cap.

Part 7 comprises a flexible wall l1 which rests against the pusher 12 mounted in an opening made in the upper part of cap 2. Once the cap is screwed onto bottle l, the two parts 5 and 7 are clamped together in such a way as to form a joint which is tight towards the liquid contained in the bottle and its vapor. Furthermore, chamber 4 is clamped between protruding edge 10 of the cap and the neck of bottle l, ensuring therefore a further fluid-tight closure at the bottle neck.

Parts 5 and 7 may be made of polyethylene for instance.

Part 5 may be shaped in such a form as to avoid the protruding edge 8. By exerting a pressure on the pusher l2 by a finger through the openingv 13 of the cap, the operator compresses the flexible wall 1 1 causing the air contained in chamber 4 to be expelled from this latter and to pass into the bottle. When the pressure exerted ori the pusher 12 is released, chamber 4 returns to its initial volume owing to the elasticity of the flexible wall 1l. A certain vacuum is thus created in the chamber 4 which allows the liquid contained in the bottle l to rise in the pipette. The pipette stopper may then be unscrewed from the bottle and the liquid contained therein can be dispensed drop by drop from the pipette by exerting anew a slight pressure on the pusher l2.

Tube 6 does not necessarily have to dip down to the bottom of the bottle. lt may in fact be of short length and have its lower edge at a level higher than the normal level of the liquid contained in the bottle and be connected to a glass tube which dips completely into the liquid.

Instead of being screwed onto the bottle, cap 2 may be fitted on said bottle in any different known way, for example by appropriate nesting or by a bayonet-joint. This equally applies to the assembly of chamber 4 into cap 2.

In the variation illustrated by FIG. 2 pusher 12 ofthe above embodiment is replaced by a pusher 14 which is integral with the resilient wall 11 of part 7. Said pusher is mounted in opening 13 of cap 2 and it enables wall 11 and chamber 4 of the pipette stopper to be pushed.

than that indicated in the afore-mentioned embodiments.

What l claim is:

l. A pipette stopper comprising an external cap including an inner fixing means adapted to be fitted to a receptacle such as a bottle, and a chamber within said cap, said chamber being tightly clamped between the cap and the receptacle when the cap is fitted on the receptacle, wherein the chamber includes two parts, nested into each other, one of said parts having means engaging with the inner fixing means ofthe cap so that said two parts are tightly pressed against a first protruding edge shaped in the cap when said parts are in position and wherein the fixing means of the cap engages a corresponding retaining part of the receptacle on which the cap is fitted, said engaging means of said one part including a first screw thread and said inner fixing means of said cap including a second screw thread.

:k k i 

1. A pipette stopper comprising an external cap including an inner fixing means adapted to be fitted to a receptacle such as a bottle, and a chamber within said cap, said chamber being tightly clamped between the cap and the receptacle when the cap is fitted on the receptacle, wherein the chamber includes two parts, nested into each other, one of said parts having means engaging with the inner fixing means of the cap so that said two parts are tightly pressed against a first protruding edge shaped in the cap when said parts are in position and wherein the fixing means of the cap engages a corresponding retaining part of the receptacle on which the cap is fitted, said engaging means of said one part including a first screw thread and said inner fixing means of said cap including a second screw thread. 